PBR exclusion measurement for zero and plus
= PBR exclusion measurement for zero and plus
{c}
The product preparations $00,0+,+0,++$ are excluded respectively by the orthonormal vectors $(01+10)/\sqrt2$, $(00-01+10+11)/2$, $(00+01-10+11)/2$ and $(00-11)/\sqrt2$, written in the computational basis. Each vector has zero inner product with its labelled preparation. This <projective measurement> gives <antidistinguishable quantum states> and drives the two-copy <PBR theorem> contradiction.